This invention relates to a disposable wipe-out sheet suitable for wiping out dust and/or dirt from floor or wall surfaces.
Japanese Patent Application Publication No. 1997-135798A describes a disposable wipe-out sheet comprising a heat-sealable synthetic resin base sheet and a plurality of heat-sealable synthetic resin filaments bonded to this sheet and extending in one direction. These filaments are obtained by deregistering or opening a tow of continuous filaments and bonded to the base sheet by a plurality of sealing lines extending transversely of the filaments and arranged intermittently in the one direction. The tow having been deregistered and spred transversely of the base sheet and bonded along transversely opposite side edge regions to the base sheet at sealing spots. The base side edge regions of the base sheet are folded back and heat-sealed together, respectively, to reinforce these side edge regions.
For continuous production of the well known wipe-out sheets at a predetermined high velocity, a heated block or supersonic horn extending transversely of a laminate comprising a continuous web of the base and deregistered tow is instantaneously pressed against the lamination to form the lamination with the sealing lines. However, in the case of the wipe-out sheet of prior art, there is a concern that the deregistered tow might spread excessively or insufficiently or even meander off from a predetermined straight course under a pressure of the heated block or supersonic horn. These phenomena would deteriorate the quality of the wipe-out sheet and/or decrease its yield rate.
This invention aims to prevent a tow from excessively spreading in the course of the process for making a disposable wipe-out sheet.
According to this invention, there is provided a process for making a disposable wipe-out sheet comprising a heat-sealable synthetic resin base sheet and a plurality of heat-sealable synthetic resin long fibers extending in one direction of the base sheet, and the fibers being bonded to the base sheet by a plurality of sealing lines extending transversely of the one direction and arranged intermittently in said one direction.
In such a process, this invention comprises the steps of:
a. feeding a continuous base sheet intended to become the base sheet and a tow of continuous filaments intended to become the long fibers in said one direction;
b. deregistering the tow to spread in a range narrower than a width and placing this upon the base sheet leaving transversely opposite marginal side edge regions of the base exposed as the deregistering tow is fed;
c. continuously feeding a pair of heat-sealable synthetic resin narrow sheets each in the form of ribbon along the marginal side edge regions of the base sheet to cover the marginal side edge regions of the base sheet and transversely opposite side edge regions of the deregistered tow; and
d. forming the deregistered tow and the base sheet with a plurality of sealing lines extending transversely of the one direction and arranged intermittently in the one direction and then heat-sealing the narrow sheets each in the form of ribbon with the base sheet along the side edge regions thereof as or immediately before the deregistered tow is bonded to the base sheet.
According to one preferred embodiment of this invention, the sealing lines extend transversely of the one direction so that the narrow sheets each in the form of ribbon can be heat-sealed with said fibrillated tow along its transversely opposite side edge regions thereof.